Why we observe only retarded gravitational waves, not advanced?

[Jarek Duda]

General relativity is rather solved in time symmetric way, like the least action principle condition in Einstein's field equations, what as in e.g. Wheeler-Feynman absorber theory requires symmetrically both retarded and advanced solutions.

So why seems there are only considered retarded gravitational waves?

Can we exclude being advanced wave for all observed events ( https://en.wikipedia.org/wiki/List_of_gravitational_wave_observations )? If not, should they use original chirp shapes, or maybe time reversed?

 

[Jarek Duda]

ps. made a diagram - assuming Big Crunch and solving by the least action principle, evolving backward there should be also formed black holes, which collisions for us would be advanced gravitational waves with reversed chirps.

It would be worth searching for such reversed chirps in LIGO historical data - probably getting negative result, still allowing for valuable article - starting discussion and the search for advanced gravitational waves.

If you would know somebody interested in collaboration on such article, I would gladly help ...